There are no lockers, you will just have to take your chance like everyone else, but I have never (to my knowledge) had any paint nicked at Campaign.
Draxxus Inferno would be a bit hopefull, that is really tourney paint, Campaign usually stock Draxxus Blaze.
Walkon days will have people of all skill levels, shapes and sizes and don't forget that in paintball it is teamwork that counts in the end.